so today i state clearly and with conviction america's commitment to seek the peace and security of a world without nuclear weapons. [ applause ] i'm not naive. this it goal will not be reached quickly. perhaps not in my lifetime. it will take patience and persistence. but now we, too, must ignore the voices who tell us that the world cannot change. we have to insist, yes we can. >> that was in 2009 just weeks after he was inaugurated. the following year in 2010, president obama convened the first nuclear security summit in washington. more than 40 heads of state got together to discuss among other things how to best safeguard the nuclear material that already exists around the world. that same year president obama signed a new stark treatment. an agreement between united states and russia to reduce the number of nuclear weapons in each country's arsenal. he called that his top national security priority and he got the senate to ratify it. it's hard to put a bigger exclamation point on a policy than the way he's talked about nuclear disarmament. and counterproliferation. keeping the w